This invention relates to a quaternary ammonium salt-containing polysiloxane which is useful in formulating a fiber or fabric treating agent composition having anti-microbial properties and imparting softness and home laundry durability to various fibers and fibrous materials, a method for preparing the same, and a fiber or fabric treating agent composition comprising the same.
In the prior art, quaternary ammonium salt-containing silanes as typified by 3-(trimethoxysilyl)-propyldimethyloctadecylammonium chloride are widely used as a treating agent for imparting anti-microbial properties to various fibers and fibrous materials. They are less toxic, little stimulative or sensitive to the skin, and home laundry durable on natural fibers such as cotton, but less home laundry durable on synthetic fibers such as polyester and nylon. Since the quaternary ammonium salt-containing silanes are solid, they must be delivered in the form of an alcohol solution, typically methanol solution, which undesirably increases the transportation cost. Since methanol volatilizes upon application, the solution also has a problem of environmental pollution and lacks safety because of the potential risk of ignition.
To eliminate these drawbacks, JP-A 6-101174 proposes a polysiloxane having a quaternary ammonium salt on a side chain and JP-A 6-298775 proposes a compound having a quaternary ammonium salt at either end. These siloxanes are prepared from intermediates, which are expensive since a complex process, is required for their preparation. Additionally, the resulting siloxanes somewhat lack home laundry durability since their adsorption to fibers resorts to only the quaternary ammonium salt group.
An object of the invention is to provide a novel and improved quaternary ammonium salt-containing polysiloxane which has satisfactory anti-microbial properties and when blended as a main component in a fiber or fabric treating agent composition, imparts softness to various fibers and fibrous materials and maintains the softness even after washing. Another object is to provide a method for preparing the quaternary ammonium salt-containing polysiloxane at a low cost. A further object is to provide a fiber or fabric treating agent composition comprising the quaternary ammonium salt-containing polysiloxane as a main component.
We have found that a novel polysiloxane having a quaternary ammonium salt in the siloxane skeleton is prepared by effecting alcohol-elimination reaction between xcex1,xcfx89-dihydroxydimethylpolysiloxane and a quaternary ammonium salt-containing trialkoxysilane. The starting reactants are relatively easy to prepare and hence, inexpensive. Because of inclusion of both the siloxane skeleton and the alkoxy group, the resulting polysiloxane is highly adsorptive to fibers and highly home laundry durable. Because of the lack of alcohol, the polysiloxane is safe. By using an aminosilane such as an aminopropylaminotrialkoxysilane or N-aminoethyl-3-aminopropyltrialkoxysilane in combination with the reactants, a polysiloxane containing both an amino group and a quaternary ammonium salt-containing group in the skeleton is obtained. The use of the compound has the advantage that softening and anti-microbial treatments can be accomplished at the same time.
It is noted that a siloxane having a quaternary ammonium salt in the siloxane skeleton is disclosed in JP-B49-11760. However, this polymer is used as a foam stabilizer, does not contain an alkoxy group necessary to impart home laundry durability, and does not utilize alcohol-elimination reaction for its synthesis. This polymer is different from the inventive polymer.
Accordingly, the present invention in a first aspect provides a quaternary ammonium salt-containing polysiloxane comprising at least one unit of the following general formula (1): 
wherein R1 is a substituted or unsubstituted monovalent organic group of 1 to 20 carbon atoms, R2 is a monovalent organic group containing at least one quaternary ammonium salt, R3 is an organoxy group represented by xe2x80x94OR1, and p is a positive number of 2 to 2,000.
In a second aspect, the invention provides a quaternary ammonium salt-containing polysiloxane comprising at least one terminal group of the following general formula (2): 
Wherein R1, R2 and R3 are as defined above, and xe2x80x9caxe2x80x9d is equal to 0 or 1.
In a third aspect, the invention provides a method for preparing the quaternary ammonium salt-containing polysiloxane defined above, comprising effecting alcohol-elimination reaction between (A) an organopolysiloxane of the following general formula (5): 
wherein R1 and p are as defined above and (B) an organosilane of the following general formula (6): 
wherein R1, R2, and R3 are as defined above and xe2x80x9caxe2x80x9d is 0 or 1.
Also contemplated herein is a fiber or fabric treating agent composition comprising the quaternary ammonium salt-containing polysiloxane defined above as a main component.
In the present invention, the quaternary ammonium salt-containing polysiloxane is defined as comprising at least one unit of the general formula (1) and/or the general formula (2): 
wherein R1 is a substituted or unsubstituted monovalent organic group of 1 to 20 carbon atoms, R2 is a monovalent organic group containing at least one quaternary ammonium salt, R3 is an organoxy group represented by xe2x80x94OR1, and p is a positive number of 2 to 2,000. 
wherein R1, R2, and R3 are as defined above, and xe2x80x9caxe2x80x9d is equal to 0 or 1.
The organic groups represented by R1 are substituted or unsubstituted monovalent organic groups of 1 to 20 carbon atoms, especially 1 to 3 carbon atoms. Illustrative examples of R1 in the organopolysiloxane include alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, decyl, dodecyl, tetradecyl, octadecyl and eicosyl; alkenyl groups such as vinyl, allyl, propenyl, butenyl and hexenyl; aryl groups such as phenyl and tolyl; aralkyl groups such as benzyl, phenylethyl, and phenylpropyl; cycloalkyl groups such as cyclopentyl and cyclohexyl; and substituted ones of the foregoing groups in which some or all of the hydrogen atoms attached to carbon atoms are replaced by halogen atoms, for example, halogenated alkyl groups such as chloromethyl, trifluoropropyl and chlorophenyl, and halogenated aryl groups such as halogenated phenyl. Of these, it is preferred that methyl, phenyl and/or trifluoropropyl account for at least 90 mol % of the R1 groups.
Moreover, in the monovalent hydrocarbon groups (typically alkyl) represented by R1, some of the hydrogen atoms may be replaced by monovalent nitrogenous organic groups such as amino and alkylamino groups. Alternatively, the monovalent hydrocarbon groups represented by R1 may be separated by dibalent nitrogenous organic groups such as NH, NCH3 and NC2H5 groups.
In formula (1), R2 is a monovalent organic group containing at least one quaternary ammonium salt, preferably a monovalent organic group of the following general formula (3):
xe2x80x94CH2CH2CH2N+R4R5R6Clxe2x88x92xe2x80x83xe2x80x83(3)
wherein R4 and R5, which may be the same or different, are each a monovalent hydrocarbon group of 1 to 3 carbon atoms, and R6 is a monovalent hydrocarbon group of 1 to 30 carbon atoms. More preferably, R2 is a monovalent organic group of the following general formula (4):
xe2x80x94CH2CH2CH2N+(CH3)2CnH2n+1Clxe2x88x92xe2x80x83xe2x80x83(4)
wherein n is a positive number of 12 to 24. Examples of the monovalent hydrocarbon groups represented by R4, R5 and R6 are as exemplified above for R1, examples of R4 and R5 being of 1 to 3 carbon atoms and examples of R6 being of 1 to 30 carbon atoms. Most preferably, R2 is
xe2x80x94CH2CH2CH2N+(CH3)2C18H37Clxe2x88x92 or xe2x80x94CH2CH2CH2N+(CH3)2CH2CH6H5Clxe2x88x92.
R3 is an organoxy group represented by xe2x80x94OR1, preferably an alkoxy group of 1 to 6 carbon atoms. Illustrative examples of R3 are methoxy, ethoxy, and propoxy groups, with the methoxy being most preferred.
Letter p is a positive number of 2 to 2,000. Preferably p is at least 10. Also preferably p is up to 1,000, and especially up to 100. If p is more than 2,000, the content of quaternary ammonium salt becomes relatively low, which detracts from anti-microbial properties.
The quaternary ammonium salt-containing polysiloxane comprising at least one unit of the formula (1) may have any desired terminal group. Exemplary terminal groups are dialkylhydroxysilyl, trialkylsilyl, alkyldialkoxysilyl and dialkylalkoxy groups. Of these, dialkylhydroxysilyl, trialkylsilyl and alkyldialkoxysilyl groups are preferred from the stability standpoint. More preferred terminal groups are of the above general formula (2).
The polysiloxanes of the invention are typically represented by the following general formula (I). 
Herein, R1, R2, R3 and p are as defined above, Rxe2x80x2 is xe2x80x94SiR12OH, xe2x80x94SiR12R3, xe2x80x94SiR1R32 or xe2x80x94SiR1aR2R32xe2x88x92a, two Rxe2x80x2 groups may be the same or different, q is a number of 0 to 30, preferably 1 to 30, and especially equal to 1, 2 or 3 with proviso that the polysiloxane has at least one R2 and at least one R3 in a molecule.
Illustrative examples of the quaternary ammonium salt-containing polysiloxane comprising at least one unit of the formula (1) are given below. 
The quaternary ammonium salt-containing polysiloxane of the invention can be prepared by effecting alcohol-elimination reaction between (A) a both end hydroxyl-blocked Is organopolysiloxane of the following general formula (5) and (B) a quaternary ammonium salt-containing organosilane of the following general formula (6). 
Herein R1, R2, R3, p and xe2x80x9caxe2x80x9d are as defined above.
In formula (5), p is a positive number of 2 to 2,000 as mentioned above. If p is less than 2, the silanol becomes unstable, allowing condensation reaction to take place parallel to the reaction with component (B), resulting in cyclic by-products. R1 is as defined above, and preferably at least 90 mol % of R1 is methyl, phenyl and/or trifluoropropyl. Illustrative examples of the silanol of formula (5) are given below. 
In formula (6), R2 and R3 are as defined in formula (1). It is preferred that R2 be a monovalent organic group of the general formula (3):
xe2x80x94CH2CH2CH2N+R4R5R6Clxe2x88x92xe2x80x83xe2x80x83(3),
and especially xe2x80x94CH2CH2CH2N+(CH3)2C18H37Cxe2x88x92 because the corresponding component (B) is effectively reactive with component (A) and ensures ease of synthesis as well as high anti-microbial properties.
R3 is most preferably a methoxy group which allows for smooth progress of alcohol-elimination reaction. Illustrative examples of formula (6) are:
(CH3O)3SiCH2CH2CH2N+(CH3)2C18H37Clxe2x88x92 and
(CH3O)3SiCH2CH2CH2N+(CH3)2CH2C6H5Clxe2x88x92.
If desired, an aminosilane is used as component (C) in combination with the silane of formula (6). Examples of the aminosilane are given below.
(CH3O)3SiCH2CH2CH2NH2
(CH3O)3SiCH2CH2CH2NHCH2CH2NH2
(CH3O)3SiCH2CH2CH2CH2NHCH2CH2NHCH2CH2NH2

The conditions for reaction between components (A) and (B) preferably include a temperature of about 50 to 180xc2x0 C. and a time of about 3 to 20 hours although the reaction conditions vary depending on the reactivity of the silanol (A) and the reactivity of the organoxy group, especially alkoxy group in component (B). By effecting reaction under such conditions, the quaternary ammonium salt-containing polysiloxane of formula (1) is readily obtained.
It is noted that since the quaternary ammonium salt as component (B) is generally available in the form of an alcohol solution, typically methanol solution, reaction must be effected in the alcohol solution or the alcohol must be removed prior to reaction. In order that efficient reaction proceed, reaction is preferably effected while removing the alcohol from the system.
As mentioned above, the aminosilane (C) may be used in addition to components (A) and (B) because the aminosilane promotes the alcohol-elimination reaction. The solvent need not be used. If component (A) or the product is viscous, a solvent such as toluene or xylene is conveniently used for the reaction.
Components (A) and (B) are preferably used in such amounts that the: molar ratio of (A)/(B) may range from 0.5/1 to 2.0/1. If (A)/(B) is greater than 2, a more amount of the quaternary ammonium salt-free polysiloxane is left. If (A)/(B) is less than 0.5, a more amount of the quaternary ammonium silane is left.
The thus obtained polysiloxane should preferably contain at least 0.05% by weight of quaternary nitrogen atoms. A quaternary nitrogen atom content of less than 0.05% by weight may fail to exert a satisfactory antimicrobial action.
It is a common practice in the art to modify amino group-containing polysiloxanes by reacting with organic acids, inorganic acids or epoxy compounds. Where the quaternary ammonium salt-containing polysiloxane of the invention is prepared using the aminosilane (C) during reaction between components (A) and (B), the polysiloxane is then optionally modified with organic acids, inorganic acids or epoxy compounds. For example, modification is optionally effected with organic acids, inorganic acids or epoxy compounds in order that one or two hydrogen atoms of NH or NH2 be replaced by COR or CH2CH(OH)CH2O(C2H4O)nR7 wherein R is an alkyl group of 1 to 10 carbon atoms, R7 is hydrogen or a monovalent hydrocarbon group, typically an alkyl group of 1 to 8 carbon atoms, and n is a positive number of 0 to 10. Exemplary organic acids are formic acid, acetic acid, acetic anhydride and propanoic acid, with acetic acid and acetic anhydride being preferred. Exemplary inorganic acids are hydrochloric acid and phosphoric acid.
Examples of the epoxy compound which can be used for modification are those of the following general formula (8): 
wherein R8 is hydrogen or a monovalent hydrocarbon group, typically an alkyl group of 1 to 8 carbon atoms, and m is a positive number of 0 to 10. R8 is preferably hydrogen or butyl.
The fiber or fabric treating agent composition comprising the quaternary ammonium salt-containing polysiloxane according to the invention is typically prepared by dissolving the polysiloxane in organic solvents such as toluene, xylene, n-hexane, n-heptane, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, butyl acetate, and mineral turpentine; or as emulsions using nonionic, anionic, cationic or ampholytic surfactants. Although the emulsifiers used herein are not critical, exemplary nonionic surfactants include ethoxylated higher alcohols, ethoxylated alkyl phenols, polyhydric alcohol fatty acid esters, ethoxylated polyhydric alcohol fatty acid esters, ethoxylated fatty acids, ethoxylated fatty acid amides, sorbitol, sorbitan fatty acid esters, ethoxylated sorbitan fatty acid esters, and sucrose fatty acid esters, with their HLB being preferably in the range of 5 to 20, especially 10 to 16. Exemplary anionic emulsifiers include higher alcohol sulfate ester salts, alkyl phenyl ether sulfate ester salts, alkylbenzenesulfonate, higher alcohol phosphate ester salts, ethoxylated higher alcohol sulfate ester salts, ethoxylated alkyl phenyl ether sulfate ester salts, and ethoxylated higher alcohol phosphate salts. Exemplary cationic emulsifiers include alkyltrimethylammonium chlorides, alkylamine hydrochlorides, coconut amine acetate, alkylamine acetates, and alkyl-benzenedimethylammonium chlorides. Exemplary ampholytic surfactants include N-acylamidopropyl-N,N-dimethylammonium-betaines and N-acylamidopropyl-N,Nxe2x80x2-dimethyl-Nxe2x80x2-xcex2-hydroxy-propylammoniobetaines. An appropriate amount of the emulsifier or surfactant used is about 5 to 50 parts, more preferably about 10 to 30 parts by weight per 100 parts by weight of the quaternary ammonium salt-containing polysiloxane. Upon emulsification, water is preferably used in such an amount as to give a quaternary ammonium salt-containing polysiloxane concentration of about 10 to 80% by weight, especially about 20 to 60% by weight.
The emulsion may be prepared by prior art well-known methods. For example, the organopolysiloxane is mixed with a surfactant and emulsified in water by means of an emulsifying machine such as a homomixer, homogenizer, colloid mill, line mixer, Universal Mixer(copyright), Ultra Mixer(copyright), Planetary Mixer(copyright), Combi Mix(copyright) or three-roll mixer.
In the fiber or fabric treating agent composition, additives may be added insofar as they do not compromise the benefits of the invention. Suitable additives are anti-creasing agents, flame retardants, anti-static agents, anti-oxidants, preservatives, and anti-rusting agents.
A variety of fibers and fibrous materials can be treated with the inventive fiber or fabric treating agent composition, for example, by adjusting the emulsion of the composition to a suitable concentration, and applying the emulsion to fiber or fabrics as by dipping, spraying or roll coating. The amount of the composition applied to fiber or fabrics is not critical and varies with the type of fiber or fabrics. As a general rule, an appropriate coating weight of the quaternary ammonium salt-containing polysiloxane is about 0.01 to 10% by weight based on the weight of fiber or fabrics. The coated fibers are then dried by hot air blowing or in a heating furnace. The drying conditions include about 100 to 150xc2x0 C. and about 2 to 5 minutes though they vary with the type of fiber or fabrics.
Any desired type of fiber or fibrous material can be treated with the inventive fiber or fabric treating agent composition. The composition is effectively applicable to either natural fibers such as cotton, silk, hemp, wool, Angora and mohair, or synthetic fibers such as polyester, Enylon, acrylic and urethane spandex. Also the form and shape of fiber or fibrous material are not critical. Not only raw material forms such as staples, filaments, tows and threads, but also a variety of worked products including woven fabric, knitted fabric, wadding, and non-woven fabric can be treated with the inventive fiber or fabric treating agent composition.
There has been described a quaternary ammonium salt-containing polysiloxane which is useful in formulating a fiber or fabric treating agent composition for imparting anti-microbial properties, softness and home laundry durability to various fibers and fibrous materials.